Fumigation of grain



y 1963 J. c. DAWSON ETAL 3,097,916

FUMIGATION 0F GRAIN 3 Sheets-Sheet 1 Original Filed July 6, 1959 Jail- 1k Can/ 0W,

y 1963 J, c. DAWSON ETAL 3,097,916

FUMIGATION OF GRAIN 3 Sheets-Sheet 2 Original Filed July 6, 1959 FIGS.

FIG .4.

FIG.3.

July 16, 1963 J, c. DAWSON ETAL 3,097,916

FUMIGATION OF GRAIN Original Filed July 6, 1959 s sheets-swat 3 [4| 7I23 in I 65- i f 139 P I 53 n I J. i t i- United States Patent 3,097,916FUMIGATION OF GRAIN Joseph Carl Dawson and Raymond P. Millard, Ferguson,Mo., assignors to Ferguson Fumigants, Inc., Ferguson, Mo., a corporationof Missouri Original application July 6, 1959, Ser. No. 825,168, nowPatent No. 3,041,684, dated July 3, 1962. Divided and this applicationOct. 5, 1961, Ser. No. 143,169 3 Claims. (Cl. 21-58) This inventionrelates to the fumigation of grain (such as wheat, corn, oats, rye,barley and rice), and more particularly to a method of fumigating grainin storage in a grain storage structure.

This application is a division of our copending application Serial No.825,168, filed July 6, 1959, now U.S. Patent No. 3,041,684, issued July3, 1962, and entitled Fumigation of Grain.

Grain is frequently stored in bulk in a grain storage building, thistype of storage being referred to as flat storage. Such buildingsfrequently have one or more roof Ventilators and one or more perforatedair ducts extending along the floor of the building and through a wallof the building to a connection with the inlet end of a fan housinglocated outside the building, the exhaust or outlet end of the fanhousing being open to the atmosphere. The grain is piled up inbulk inthe building over the air duct, the duct being adapted for entry of airthrough its perforations without entry of grain to avoid clogging. Withthe fan in operation to exhaust air from the duct, air is drawn into thebuilding through the roof ventilator (or .ventilators), flows downthrough the grain, enters the duct through the perforations in the duct,and is exhausted back to the outside by the fan through the fan outlet.This arrangement is used for cooling the grain and to control moisturemigration in the grain.

Among the several objects of this invention may be noted the provisionof a method utilizing the duct and fan such as have heretofore been usedfor cooling (for the additional purpose of fun-ligating the grain,fumigation being accomplished by recirculating air containing vaporizedfurnigant through the grain for as long a time as required to effecteven distribution of the fumigant throughout the grain thereby to insurekilling of insects throughout the grain; the provision of a method suchas described which enables arrangements to be quickly and economicallymade for utilizing a roof opening (such as the roof ventilator in thecase of a storage building or the manhole in the case of a silo) and theduct and fan for recirculating air through the grain and for introducingfumigant into the recirculating air for most efiective fumigation; theprovision of a method such as described which enables the use ofportable equipment adapted to be readily transported from building tobuilding or silo to silo, including means for providing recirculatingductwork adapted to be compactly packed and transported fromplace-to-place and to be re-used many times, and including a portablebulk liquid fumigant supply; and the provision of a method such asdescribed which is safe to use (noting the toxicity of the fumigant) andwhich fills a need for economically and effectively fumigating grain instorage in grain storage buildings and silos of the class described.

'Other objects and features will be in part apparent and in part pointedout hereinafter.

The invention accordingly comprises the methods hereinafter described,the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possibleembodiments of the invention are illustrated,

FIG. 1 is a view in elevation with parts broken away and shown insection of a grain storage building installation being fumigated by themethod of this invention;

HG. 2 is an enlargement of a portion of FIG. 1 with parts broken awayand shown in section;

FIG. 3 is an enlargement of another portion of FIG. 1 with parts brokenaway and shown in section;

FIG. 4 is an enlarged section taken on line 44 of FIG. 3;

FIG. 5 is a plan of fumigant supply vehicle used in carrying out theinvent-ion;

'FIG. 6 is a vertical section of a silo illustrating the method of thisinvention as applied thereto; and

FIG. 7 is an enlarged fragment of FIG. 6 with parts further broken awayand shown in section.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawlngs.

Referring to FIG. 1 of the drawings, there is indicated at 1 a grainstorage building of the class above described having end walls such asindicated at 3, side walls such as indicated at 5, and a gable roof 7. Aconventional roof ventilator 9 (see FIGS. 1 and 3) of the typecomprising a ventilator stack 11 and a weather cap 13 for the stack isshown on the roof ridge. Only one such ventilator appears =in FIG. 1,but it will be understood that there may be several ventilators spacedalong the roof ridge. A perforated air duct 15 is shown extending justabove the floor 17 of the building from near one side of the wallthrough a collar 19 around an opening in the other side of the building.Supports for the duct are indicated at 21. The perforations in the ductare indicated at 23. These are either too small for passage of grain, orscreening may be provided to prevent clogging by grain.

The outer end of the duct (which, outside the building, is imperforate)is connected to the inlet end 25 of a fan housing 27 which is mounted onthe ground outside the building. The fan blade is indicated at 29 andthe motor for driving the blade at 31. The blade is ordinarily adaptedto discharge air through the exhaust or outlet end 33 of the fanhousing, thereby inducing a flow of air down through the roof ventilatorinto the building above grain G piled up in the building over the duct15, thence down through the grain, thence into the duct, and through theduct to the inlet end 25 of the fan housing.

It will be understood that the roof will usually have one or morefilling openings (with covers therefor) for delivery of grain into thebuilding to pile up on the floor 17 over the duct 15. While the duct 15is shown as extending from side-to side of the building, it may extendfrom end-to-end. There may be several such ducts and fans. Forsimplication of the disclosure herein, the invention will be describedas it pertains to a building having only one roof ventilator and one airduct and fan.

As shown in FIGS. 1 and 3 in accordance with this invention, anair-tight ventilator cover or bonnet 35 is applied to the roofventilator 9 over the weather cap 13 thereof. This cover or bonnet 35 isconstituted by what amounts to an inflatable bag made of any suitablefabric that has been treated to make it air-impervious, which may be ofcylindrical form, having a circular closure 37 at one end, and beingopen at the other end. It will be understood that the bonnet need not becylindrical, other shapes may be used if desirable to better fit aventilator.

wall. The diameter of the bonnet when inflated is greater than thediameter of the weather cap of the roof ventilator (see FIG. 3). Asapplied to the roof ventilator, the open lower end of the bonnet isgathered around the ventilator stack 11 below the cap 13, and securedtightly around the stack by suitable means which may consist simply of arope 51 tied tightly around the gathered lower end of the bonnet. Thisprovides a reasonably air-tight seal between the lower end of the bonnetand the stack. Tubular arm 39 is made of the same material as bonnet 35.

As shown in FIGS. 1 and 2, an air-tight plenum chamber 53 is applied tothe outlet end 33 of the fan housing 27. This plenum chamber, similarlyto the bonnet 35, is constituted by what amounts to an inflatable bagmade of any suitable fabric that has been treated to make itair-impervious. As herein illustrated, this plenum chamber is of squarecross section, to fit a square fan housing outlet, being dimensioned tofit over the outlet. It is open at one end to fit over the outlet, andhas a square closure 55 at its other (outer) end. Extending upward fromthe top wall of the plenum chamber is a tubular connector arm 57.Incorporated in this arm, as by being retained in a hem 59 on the arm,is a substantially rigid clamping ring 61 (like ring 43). As applied tothe outlet end 33 of fan housing 27, the open end of the infiatableplenum chamber is secured tightly to the housing by suitable means,which may consist simply of a rope 63 tied tightly around the end of theplenum chamber. This provides a reasonably air-tight seal between theinner end of the plenum chamber and the tan housing. It will beunderstood that the plenum chamber need not be of square cross section;it may be made of other shapes to fit different fans.

A length of air-tight flexible inflatable tubing 65 is connected betweenthe arm 57 of the plenum chamber 53 and the arm 39 of the bonnet 35.This tubing may consist of conventional commercially availablepolyethylene tubing, for example, of such size as to fit over the arms57 and 39. A suitable length of the tubing to extend from arm 57 to arm39 for any given installation may be unwound from a supply roll of thetubing and cut off. The ends of the length of tubing are applied overthe arms 57 and 39, and over the clamping rings 61 and 43 of these arms,and clamped in air-tight manner thereon as by means of clamping straps67 of arcuate cross section (see FIG. 4) which are clamped around therings. Each of the clamping straps may consist, for example, of a lengthof longitudinally split flexible plastic tubing provided with means suchas indicated at 69 at its ends for drawing it tight around the ring.

The above-described arrangement is such as to provide a closed circuitfor recirculation of air through the grain G in building 1, this circuitbeing as follows: from plenum chamber 53 through plenum chamber arm 57,tubing 65, bonnet arm 39, bonnet 35, roof ventilator stack 11, thencedown through the grain G, into the duct 15, through the duct back to thefan housing, and thence into the plenum chamber. With the fan inoperation, the plenum chamber 53, the tubing 65 and the bonnet 35 areinflated by reason of the air pressure caused by the fan so as to beopen for flow of air therethrough.

Referring to FIGS. 1 and 5 of the drawings, there is indicated at 71 avehicle trailer carrying a pressure vessel 73 which contains a supply ofliquid fu-migant, more particularly an ethylene dibromide-methyl bromidefurnigan-t such as disclosed in Dawson US. Patent 2,606,857. The vesselis strapped down on the bed of the trailer as by cables 75. A fillinginlet for filling the vessel with fumigant is indicated at 77. Thisfilling inlet includes a cut-01f valve 79 and a check valve 81 adaptedto close outwardly .to prevent escape of fumigant from the vessel incase the filling line through which .fumigant is delivered to the vesselis disconnected without closing the cut-off valve 79. Compressed air issupplied to the vessel as from an air compressor 83 mounted on the bedof the trailer for forcing fumi'gant from the vessel through a deliveryline 85. At the inner end of line 85 within the vessel 73 there is anexcess flow valve 85a. Outside vessel 73, line 85 includes a cut-offvalve 86, a filter 87 (such as a glass wool filter) for filtering thefumigant, a hydrostatic relief st-andpipe 89 (which appears in plan inFIG. 5), and a meter 91 for measuring the flow of furnigant. Excess flowvalve 85a is of a known type adapted to cut off flow of fumigant fromthe vessel if valve 86 should break oil in an accident. Line 85 isconnected to the inlet of a cut-off valve 93. A header 95 is connectedto the outlet of valve 93. Connected to the header are a plurality ofcocks 97, each adapted for connection of a hose thereto. Six such cocksare shown. The compressor 83 delivers air to a T 99, from which there isan air line 101 to the vessel 73 including a dryer 103, a check valve105 and a cut-off valve 107, also an air line 109 to an auxiliaryblow-oil air tank 111. An air line 113 including a cut-off valve 115connects tank 111 to the header 95. A pressure gauge 117 is provided forindicating the air pressure in the vessel, and a safety valve 119 isprovided for relieving excess pressure in the vessel. The compressor isdriven by an electric motor E, which may be powered from the vehiclehauling the trailer, or item the source of power for the fan on the job.It will be understood that vessel 73 and its appurtenances may bemounted on a truck instead of a trailer.

As shown in FIGS. 1 and 3, a furnigant delivery hose 121, such as aplastic hose, is connected between one of the cocks 97 and the outer endof the hose connector fitting 47 of the bonnet 35. Another hose 123,such as a plastic hose, is connected to the inner end of connectorfitting 47 and is inserted in the ventilator stack 11, hanging down inthe stack. At the lower end of hose 123 is a nozzle 125. This ispreferably of a type having interchangeable orifices whereby its rate ofdischarge may be changed.

Operation is as follows:

The amount of tumigant required for fumigation on the particular job isdetermined. This is dependent on such factors as the cubic footage ofthe building, the average temperature of the grain, and the leakage tobe expected from the building. With the fan 29 in operation, manometerreadings are taken to determine the rate of flow of air throughdifferent regions of the grain mass. This rate may vary considerablyfrom region to region. From the manometer readings, a determination ismade of the time required for a single pass of air through the region ofleast resistance to flow of air down through the grain and the timerequired for a single pass of air through the region of highestresistance. Then, an orifice is selected for nozzle such as will deliverthe required dosage in a length of time approximating the time requiredfor a single pass of air through the region of least resistance.Assuming, for example, that it takes five minutes for a single pass ofair through the region of least resistance, an orifice is used in nozzle125 that will deliver the required dosage in about five minutes (:forthe particular predetermined air pressure supplied to the vessel 73 bythe air compressor 83, which may be sufiicient to provide a pressure of1100 p.s.i., for example, at the nozzle 125, and which is maintainedconstant throughout the delivery of the fumigant) The fan 29 is operatedto cause circulation of air through the grain G in building 1 as abovedescribed. With predetermined air pressure in the vessel 73, the headervalve 93, valve 86 and the cock 97 for the hose leading up to the bonnet35 are opened. The remaining cocks 97 are left closed. Air valve 115 isclosed. Fumigant is thereby delivered from the vessel 73 through hoses121 and 123 and sprays out of nozzle 125 into the air above the grain Gat the proper rate for delivery of the required dosage in the length oftime required for a single pass of air through the region of leastresistance to flow of air. The furnigant disperses in the air and iscarried down with the air through the grain. When the predetermineddosage of frnnigant has been delivered from the vessel 73, as determinedby observation of the meter 91, the header valve 93 is closed to out offthe flow. Then, the air valve 115 is opened for delivery of air fromauxiliary tank 111 to the header 95 to blow off the header and hoselines 121 land 1 23 to clear them of fumigant and to provide for fulldelivery of the measured amount of dumigant into the bui=lding. A-fiterthe header 95 and hose lines 121 and 123 have been cleared, the airvalve 115 is closed. The fan 29 is maintained in operation to providefor recirculation of the air containing the vaporized fumigant throughthe grain for as long a time as required to accomplish substantiallyeven distribution of fumigant throughout the mass of the, grain toeffect a complete kill of insects which may be ini'esting the grain.This will be at least the time required for a single pass of air throughthe region of highest resistance to flow of air, and ordinarily, torthoroughness, will be twice that time.

After fumigation as above described has been completed, the hose 121 isdisconnected from the cock 97 and the bonnet connector 47 and coiled up,the plastic tubing 65 is disconnected from the bonnet and plenum chamberarms 39 and 57 by releasing the clamping straps 67, the bonnet 35 isremoved from the ventilator 9 by untying rope 51, and the plenum chamber53 is removed from the fan housing by untying the rope 63. The bonnet 35and plenum chamber 53 are collapsed and packed in compact manner andtaken to the next job for re-use. Tubing 65 may be re-used on anotherjob where its length is suitable. It will be understood that on the nextjob, the same set up as above described will be made. Spraying thefumigant into the air above the grain avoids action of the fumigant as arefrigerant such as would tend to condense and freeze moisture in theair on humid days.

In the case of a building having several roof ventilators, and one airduct and fan, only one of the roof ventilators will have a bonnet 35applied thereto. The remaining roof ventilators will be blocked ofi asby applying polyethylene bags thereover, gathering the open lower endsof the bags around the ventilator stacks, and tying ropes around thegathered lower ends of the bags.

In some instances, it may be desirable to provide for delivery of air bya single fan to two or more roof ventilators. In such case, a specialplenum chamber having a plurality of outlet arms such as the arm 57 maybe used, plastic tubes 65 being connected between these arms and thearms 39 on bonnets 35 applied to the roof ventilators. Fumigant hoselines such as the line 121 may then be run from as many of the cocks 97as there are bonnets 35 to the bonnets. Having a plurality of cocks 97also enables simultaneous delivery of fumigant to a plurality of systemssuch as shown in FIG. 1. This is useful, for example, in regard to abuilding having a plurality of air ducts and fans and a correspondingplurality of roof ventilators.

Referring to FIG. 6 of the drawings, there is indicated at 131 a silohaving a hopper bottom 133 and a top 135 provided with a hole 137 suchas a manhole. Extending across the hopper is an air duct 139. The outerend of the duct outside the hopper is connected to the inlet end 25 of afan housing 27, similarly to the above. Duct 139 may be a perforatedduct or one having a slot along its bottom. A special bonnet 141, to bedescribed, is applied to the top 135 of the silo at the manhole 137. Aplenum chamber 53, the same as above described, is applied to the outletend 33 of the fan housing 27. A length of airtight flexible inflatabletubing 65 is connected between the plenum chamber 53 and the bonnet 141.

lBonnet 141 comprises an inflatable bag, which may be of cylindricalform, having a closure 143 at the top and being open at the bottom.Adjacent its open end, two inflatable tubes 145 and 147 are secured tothe outside thereof, these tubes being spaced heightwise of the bonnet.The upper tube 145 has a filling valve 149, and a tube 151 is providedon the inside of the bonnet connecting the two tubes 145 and 147 (seeFIG. 7). The bonnet has a lateral arm 39, a fitting 47 for connection offumigant delivery hose 1:21, a hose 123 and a nozzle 125 the same asbonnet 35 above described.

With tubes 145 and 147 deflated, the lower end of bonnet 141 is insertedin the manhole 137. Then tubes 145 and 147 are inflated (a hand pump maybe used). When inflated, the lower tube 147 engages the bottom surfaceof silo top around the hole 137 and the upper tube engages the uppersurface of silo top 135 around the hole 137 to provide a substantiallyair-tight seal between the lower end of the bonnet and the silo top.Fumigation is carried out with this installation in essentially the samemanner as above described for the building 1.

-In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above methods without departingfrom the scope of the invention, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A method of fumigating grain in storage in a grain storage structurewhich has an opening at the top and an air duct at the bottom having aconnection with a fan outside the structure adapted to cause movement ofair vertically through the grain, comprising the steps of applying anair-tight bonnet of flexible sheet material in substantially air-tightmanner to the structure at said top opening, said bonnet having anopening for flow of air, applying an air-tight plenum chamber offlexible sheet material in substantially air-tight manner to the fan,said plenum chamber having an opening for flow of air, connecting alength of air-tight flexible tubing between the plenum chamber and thebonnet openings, operating said fan to circulate air through the grain,introducing furnigant into the air, and maintaining the circulation ofthe air for a period of time such as to distribute the fumigantsubstantially evenly throughout the grain.

2. The method of fumigating grain in flat storage in a grain storagebuilding which has a roof ventilator, a perforated air duct extendingalong the floor of the building to a connection with the inlet of a fanadapted to draw air down through the grain and into the duct and toexhaust the air through the fan outlet on the outside of the building,comprising the steps of applying an inflatable bonnet 0f flexible sheetmaterial in substantially air-tight manner over the roof ventilator,said bonnet having an air inlet, applying an inflatable plenum chamberof flexible sheet material in substantially air-tight manner to the fanoutlet, said plenum chamber having an air outlet, connecting a length offlexible inflatable tubing between the plenum chamber air outlet and thebonnet air inlet, operating said fan to inflate the plenum chamber, thetubing and the bonnet and to cause a closed circulation of air downthrough the grain, into the duct, thence out to the fan, into the plenumchamber, up through the tubing into the bonnet and down through the roofventilator, introducing a dose of fumigant into the air circulating asdescribed, and maintaining the circulation of the air for a period oftime such as to distribute the fumigant substantially evenly throughoutthe grain.

3. The method of fumigating grain in storage in a silo which has anopening at the top and an air duct extending horizontally adjacent thebottom to a connection with the inlet of a fan adapted to draw air downthrough the grain and into the duct and to exhaust the air through theham outlet on the outside of the silo, comprising the steps of applyingan inflatable bonnet of flexible sheet material in substantiallyair-tight manner to the silo over said top opening, said bonnet havingan air inlet, applying an inflatable plenum chamber of flexible sheetmaterial in substantially air-tight manner to the fan outlet, saidplenum chamber having an air outlet, connecting a length of flexibleinflatable tubing between the plenum chamber air outlet and the bonnetair inlet, operating said fan to inflate the plenum chamber, the tubingand the bonnet and to cause a closed circulation of air down through thegrain, into the duct, thence out to the fan, into the plenum chamber, upthrough the tubing into the bonnet and down through said top opening,introducing a dose of fumigant into the air circulating as described,and maintaining the circulation of the air for a period of time such asto distribute the fumigant substantially evenly throughout [the grain.

References Cited in the file of this patent UNITED STATES PATENTS1,928,903 Manning Oct. 3, 1933 2,254,276 Ellis Sept. 2, 1941 102,375,226 Higgins May 8, 1945 2,461,649 Manning Feb. 15, 1949

1. A METHOD OF FUMIGATING GRAIN IN STORAGE IN A GRAIN STORAGE STUCTUREWHICH HAS AN OPENING AT THE TOP AND AN AIR DUCT AT THE BOTTOM HAVING ACONNECTION WITH A FAN OUTSIDE THE STRUCTURE ADAPTED TO CAUSE MOVEMENT OFAIR VERTICALLY THROUGH THE GRAIN, COMPRISING THE STEPS OF APPLYING ANAIR-TIGHT BONNET OF FLEXIBLE SHEET MATERIAL IN SUBSTANTIALLY AIR-TIGHTMANNER TO THE STRUCTURE AT SAID TOP OPENING, SAID BONNET HAVING ANOPENING FOR FLOW OF AIR, APPLYING AN AIR-TIGHT PLENUM CHAMBER OFFLEXIBLE SHEET MATERIAL IN SUBSTANTIALLY AIR-TIGHT MANNER TO THE FAN,SAID PLENUM CHAMBER HAVING AN OPENING FOR FLOW OF AIR, CONNECTING ALENGTH OF AIR-TIGHT FLEXIBLE TUBING BETWEEN THE PLENUM CHAMBER AND THEBONNET OPENINGS, OPERATING SAID FAN TO CIRCULATE AIR THROUGH THE GRAIN,INTRODUCING FUMIGANT INTO TH AIR, AND MAINTAINING THE CIRCULATION OF THEAIR FOR A PERIOD OF TIME SUCH AS TO DISTRUBUTE THE FUMIGANTSUBSTANTIALLY EVENLY THROUGHOUT THE GRAIN.